Tecumseh Engine Speed

mxyplxJune 19, 2014

I am refurbishing my old Craftsman (Tecumseh) engine model 143.394172 new about 1988. It has a 2 speed carb. Haven't used it for 3 years.

Anyway when last I was using it, if I put it on low speed it would run at low speed for a while then get progressively faster till it was running at approx 2/3 max rpm. Seemed like as the engine got hotter the rpm got higher. Somehow that throttle setting was advancing as the temp goes up.

This all occurred after the engine was maybe 20 years old. When new this didn't happen.

How can I fix it?

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If you are correct on the abnormally high operating temps, more common causes could be a partially sheared flywheel key or that it is simply not running up as well as could be IE too lean. Sae 30 oil is best.

    Bookmark   June 19, 2014 at 8:23PM
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The engine didn't overheat. The rpm increased as the engine warmed up to normal operating temp.

The carb is a fixt jet, The air cleaner filter is clean and free. Throttle shaft is not loose near as I can tell.

    Bookmark   June 20, 2014 at 5:30PM
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